SCOTLAND'S position as a ''global centre of excellence'' in the electronics industry is behind Filtronic Comtek's decision to build up its manufacturing base in the country, according to finance director John Samuel.

The group makes specialised components for mobile phone companies' base stations and its business is booming.

It is likely to take on a further 50 workers this year in Scotland and more in 1999. The Scottish workforce has about doubled in a year to 150 and will top 200 by the end of the year.

Mr Samuel explained that Scotland has the experience of the products the group manufactures, with Heriot Watt University a world leader in the microwave radio technology that it uses.

He said there had been some recruiting difficulties but the group was not expecting difficulties for East Kilbride and was quite willing to train people.

Filtronic's main Scottish factory is in Stewarton, Ayrshire, where 140 people are employed, 55 in a machine shop and the rest involved in making ferrite

components.

Demand for these is rising rapidly as the mobile telephone market expands around the world.

The group tried to acquire a site in Hamilton but the factory was not ideal and the asking price was too high.

Instead, it found a five-acre site in Peel Park, East Kilbride,

promoted by Scottish Enterprise.

''In my opinion, Peel Park is one of the best industrial sites in the West of Scotland,'' said Filtronic's Scottish director Douglas Young.

Completion of the purchase is expected shortly and an architect is working on plans for a new factory which should be ready in a year's time. Until then, the group is renting two business units at Hamilton for the expansion of the ferrite business. Early next year this will then be concentrated at the single site in East Kilbride, which will in total cost #3m.

Filtronic's business is building rapidly, with sales up 144% to #42m in the six months to November 1997, and profits up from break-even to #5.1m, a 25% increase over the half-year to May 1997.

Chairman Professor David Rhodes said the turbulent conditions in Far Eastern financial markets had not had any impact. Global mobile phone subscribers are still independently forecast to rise from 180 million now to 520 million by 2002.

Filtronic shares have performed well over the past year and edged up 10p to 469p

yesterday.

Filtronic is based in Shipley, where it has a factory, and has plants in the US and Australia. The main customer for the group is Motorola, but the biggest customer for the Scottish plants is Siemens. There are few competitors and Filtronic's components account for between 5% and 10% of the value of the finished product, although this proportion is set to rise.

Filtronic is to buy the family companies of Professor Rhodes for #11.5m. The main one is also involved in microwave radio broadcasting, manufacturing sub-systems for defence products.

The purchase will widen Filtronic's technology base and give it exposure to the cable communications infrastructure market.